Remove deprecated code 2020-06-01 (RobotLocomotion#13452)

* Remove deprecated code 2020-06-01

attic/manipulation/planner/BUILD.bazel

@@ -15,23 +15,10 @@ package(
 drake_cc_package_library(
     name = "planner",
     deps = [
-        ":constraint_relaxing_ik_rbt",
         ":rbt_differential_inverse_kinematics",
     ],
 )
 
-drake_cc_library(
-    name = "constraint_relaxing_ik_rbt",
-    srcs = ["constraint_relaxing_ik_rbt.cc"],
-    hdrs = ["constraint_relaxing_ik_rbt.h"],
-    deps = [
-        "//attic/multibody:inverse_kinematics",
-        "//attic/multibody:rigid_body_tree",
-        "//attic/multibody/parsers",
-        "//common/trajectories:piecewise_polynomial",
-    ],
-)
-
 # N.B. This is unit tested in //manipulation/planner (non-attic).
 drake_cc_library(
     name = "rbt_differential_inverse_kinematics",
@@ -45,25 +32,6 @@ drake_cc_library(
 
 # === test/ ===
 
-drake_cc_googletest(
-    name = "constraint_relaxing_ik_rbt_test",
-    timeout = "moderate",
-    srcs = ["test/constraint_relaxing_ik_rbt_test.cc"],
-    copts = ["-Wno-deprecated-declarations"],
-    data = [
-        "//manipulation/models/iiwa_description:models",
-    ],
-    # TODO(sam.creasey) This test currently times out on Mac with
-    # IPOPT.  Once IPOPT is tuned to provide better/faster IK results
-    # (see https://github.com/RobotLocomotion/drake/issues/3128 ) we
-    # should enable this test.
-    tags = ["snopt"],
-    deps = [
-        ":constraint_relaxing_ik_rbt",
-        "//common:find_resource",
-    ],
-)
-
 drake_cc_googletest(
     name = "rbt_differential_inverse_kinematics_test",
     data = [